Timing mechanism



July 8, 1969 c. E. MILLER 3,454,730

TIMING MECHANISM Filed Nov. 13, 1967 INVENTOR.

CLIFFORD E. MILLER BY {1W +Q N AT ORNEYS United States Patent 3,454,730 TIMING MECHANISM Clifford E. Miller, 5307 E. 14th St., Oakland, Calif. 94601 Filed Nov. 13, 1967, Ser. No. 682,034 Int. Cl. H01h 7/08, 43/10 US. Cl. 200-38 10 Claims ABSTRACT OF THE DISCLOSURE A number of timing actuators are arrayed about a dial to operate switch contacts. An L-shaped ribbon structure is mounted to rotate with an arbor carrying a time indicating hand and engage the timing actuators to cause closing of the switch contacts. A switch is connected in series with the motor drive and a source of power to inactivate the motor drive. The switch contacts are connected in series with an alarm which in turn are connected together in parallel with the serially connected switch and motor drive. A manually operable knob is joined to the arbor for rotating the time indicating hand when the motor drive is inactivated for zero setting the time indicating hand.

Background of the invention Timing mechanisms, such as timing clocks, which include a number of timing actuators for controlling switches to, for example, initiate the sounding of an alarm at selected times are well known. Timing clock-s of these types are disclosed in US. Patents 2,098,965 and 2,806,- 910 entitled, Clock, and issued respectively Nov. 16, 1937, and Sept. 17, 1957, to Henry C. James, Jr., and US. Patent 3,348,008 issued Oct. 17, 1967, to Clifford E. Miller, the instant applicant. These timing clocks include a number of actuators arrayed about a clock dial which are selectively moveable into the path of a switch contact closing cam. The cam is carried by a carrier which extend from the hour hand arbor of the timing clocks and is rotatable therewith. The actuators are in the form of cranks having handles extending through arcuate slots in the face of the clock circumferentially spaced about the clock dial. When the handles are positioned at the outer ends of the slots, the cranks are pivoted out of the path or the cams. Movement of the handles toward the inner ends of the slots pivots the associated cranks into the path of the cams for engagement therewith at times determined by the extent to which the cranks are inwardly pivoted. When the cams engage a crank, the contacts are closed to engage an alarm or the like. The contacts are maintained closed until the carrier moves the cams beyond the engaging crank unless the crank is pivoted out of engagement with the cams by movement of the associated handle to the outer end of the slot. Consequently, if the crank is not pivoted out of engagement with the cams, additional switch contact closures cannot be accomplished until the carrier moves the cams beyond the engaging crank.

In conducting scientific experiments, an accurate timing mechanism of the type described would be useful for indicating when steps of the experiment are to be performed. Unfortunately, the construction of the cams and the inexactness characteristics of setting the cranks to engage the cams at selected times have prevented such prior art mechanisms from being satisfactory for use where precise timing is required, particularly, where it is desired to carry-out a sequence of switch contact closures closely spaced in time. For example, the construction of the cams of the prior art timing mechanisms has limited the minimum time interval between successive switch closures to about five minutes. Furthermore, the

3,454,730. Patented July 8, 1969 accuracy with which the crank-s can be set to cause a switch contact closures at a selected time is on the order of many minutes.

Therefore, considerable advantage is to be gained by providing a timing mechanism which can be set to operate switch contacts precisely at selected times, which selected times may be at precise intervals of fractions of a minute.

Summary of the invention The present invention relates to timing mechanisms of the type having a number of timing actuators arrayed about a dial which may be preset to operate switch contacts at selected times when engaged by a cam rotating with a time indicating hand of the mechanism. More specifically, the timing mechanism of the present invention includes a particularly constructed cam for engaging the timing actuators and means for setting the timing actuators which enables the timing mechanism to be precisely set to operate the switch contacts at selected times, with successive operations able to be effected at intervals of as little as fractions of a minute. The cam is an L- shaped ribbon structure joined to one end of a conductive member which is fastened to a carrier which rotates with a time indicating hand of the mechanism. The conductive member also carries a switch contact which, depending upon the location of the fulcrum about which the conductive member turns, will contact or disengage another switch contact when the L-shaped ribbon cam engages a timing actuator. The L-shaped ribbon cam includes a first extremity which extends from the conductive member towards the actuators arrayed about the dial of the timing mechanism. The other extremity of the L-shaped ribbon cam serves to secure the ribbon cam to the conductive member. The ribbon construction of the cam minimizes the contact time between the timing actuators and the cams.

Although this enables the timing mechanism to operate the switch contacts at intervals spaced only fractions of a minute apart, precise timing is realized only if the actuators can be set precisely so that they are engaged by the cams at the exact time desired. Towards realizing this precision, an exact zero-set means is provided which together with the accurately located timing actuators provide the ability to operate the switch contacts at the exact instant in time desired. More particularly, means are provided to inactivate the power drive operating the time indicating hand of the mechanism, hence, the rotating cam which engages the timing actuators to operate the switch contacts. Indicating means are in circuit connection with the switch contacts and a source of power which activates the indicating means upon operation of the switch contacts. A manually operable mechanism is coupled to rotate the time indicating hand and cam carrier rotating therewith. To zero-set the timing mechanism, the timing actuator which is engaged by the cam when the time indicating hand is at zero on the dial is positioned in its associated slot through which its handle extends for engagement by the rotating cam when the time indicating hand is at the zero position of the dial. The power drive is inactivated by the provided means, and the time indicating hand is rotated about the dial by operating the manually operable mechanism. The time indicating hand is rotated until the cam rotating therewith engages the preset timing actuator to activate the indicating means. At the instant the indicating means is activated manual rotation of the time indicating hand is terminated. The timing mechanism is thusly precisely set at zero and readied for use. Since the timing actuators of timing mechanisms of the aforedescribed type are accurately located about the dial, the precisely zeroset timing mechanism is able to provide precise timing at intervals as small as fractions of a minute.

Accordingly, it is the object of the present invention to provide a timing mechanism which can be set to operate switch contacts precisely at selected times.

More particularly, it is an object of the present invention to provide an accurate timing mechanism which can be set to operate switch contacts at precise intervals of fractions of a minute.

Another object of the present invention is to provide a precise timing mechanism particularly suited to activate indicating means to signal the precise time for executing steps of scientific eXperiments or other multiple stepped event.

A further object of the present invention is to provide a timing mechanism which can be accurately zero-set whereby precise timing is obtained during operation.

- Still another object of the invention is to provide such a timing mechanism which while the power drive is causing movement can be set to indicate a time interval by adding the interval to the time indicated and setting the appropriate crank.

Brief description of the drawings With reference to the accompanying sheet of drawings:

FIGURE 1 is a front elevation view of a electrically powered timing mechanism with the improved cam engaging means and the zero-set means in accordance with the present invention.

FIGURE 2 is a fragmentary rear elevation view of the timing mechanism with the rear plate broken away to show the cam carrier and cam in the position just as the cam engages a timing actuator.

FIGURE 3 shows the cam carrier and cam of FIG- URE 2 after the cam carrier has advanced to the position where the cams engage the timing actuator to effect operation of the switch contacts carried by the cam carrier.

FIGURE 4 is a schematic illustration of the electrical circuit for zero-setting of the timing mechanism.

Detailed description of the preferred embodiment Referring to the drawings, particularly FIGURES 1-3, the timing mechanism 11 of the present invention includes a housing 12 which houses a synchronous drive motor coupled by a gear train to drive the arbor 13 carrying the time indicating hand 14 in the manner described and shown in aforementioned patents and patent application. In the particular embodiment illustrated, only a single time indicating hand is shown. However, as will become apparent from the following detailed description, additional timing hands advanced at different speeds could be provided.

The time indicating hand 14 is positioned adjacent a time indicating dial 16 on the front face 17 of the housing 12. In the illustrated embodiment, the dial 16 is calibrated in terms of minutes of a ninety-six minute period, and the synchronous drive motor and a gear train are arranged to effect one revolution of the arbor 13, hence, the time indicating hand 14 every ninety-six minutes.

In order that electric circuits may be closed or opened at predetermined time intervals of the ninety-six minute period, a carrier 18 is secured to and is rotated with the arbor 13. A pair of opposed switch contacts 19 and 21 born by conductive members 22 and 23 are secured to the periphery of carrier 18 by screws 24 and 26. Each of the screws 24 and 26 are of conductive material and extend into the carrier 18 to contact respective conductive extensions 27 and 28 connected to coaxial conductive slip rings 29 and 31 respectively mounted in carrier 18. Stationary brushes 32 and 33 are mounted to a terminal board 34 within the housing 12 and respectively ride on one of slip rings 29 and 31 to provide means of connecting the opposed switch contacts 19 and 21 to operate mechanlsms.

Pursuant to present invention, operation of the switch contacts 19 and 21 at selected times is accomplished by means of a plurality of timing actuators in the form of crank pins 36 accurately located at regular intervals, for example, corresponding to two minutes in the illustrated embodiment, circumferentially about the time indicating dial 16. The crank pins 36 are journalled between spaced frame plates 37 and 38 located within the housing 12. Each pin 36 has a journal section 39 and a handle portion 41 extending through the front face 17 of the housing 12 for rotating the crank pin 36 into position for engagement with a cam 42 rotated with the carrier 18 to operate the switch contacts 19 and 21. The particular construction of the cam 42 of the present invention will be described in greater detail hereinbelow. The detail of the construction of the crank pins 36 is described in the aforementioned patents and patent applications. The crank handles 41 respectively extend through a plurality of arcuate slots 43 defined in the front face 17 at circumferentially spaced locations about the dial 16. The arcuate slots 43 are located exactly at two mintue intervals about the dial 16, with each slot 43 allowing the crank pin 36 extending therethrough to be positioned for engagement with the rotating cam 42 at fractions of the two minute interval. The handle portions 41 of the crank pins 36 extend sufficiently through the arcuate slots 43 to permit them to be grasped to position the crank pins 36 at the desired location within the respective arcuate slots 43.

The crank pins 36 normally are positioned with their respective handle portions 41 at the outer ends 44 of their respective slots 41. In this position, the crank pins 36 are out of engagement with the cam 42- rotated with the carrier 18. Positioning of the handle portions 41 toward the inner ends 46 of the slots 41 swings the crank pins 36 into the path of the cam 42. As the carrier 18 rotates with the time indicating hand, the cam 42 will engage the crank pins 36 of associated with the inwardly positioned handle portions 41 to be actuated to operate the switch contacts 19 and 21. The extent to which the handle portion 41 is positioned inward towards the inner end 46 of the slot 41 determines the particular fraction of the two minute interval, hence, second of the ninety-six minute period, at which the cam 42 will operate the switch contacts 19 and 21. A flat-leaf spring 47 wound about the inner ends of the crank pins 36 as shown in FIGURES 2 and 3 provide sufficient friction force to prevent the crank pins from rotating, i.e., changing their position, when engaged by the cam 42.

The particular construction of the cam 42 of the present invention enables operation of the switch contacts 19 and 21 at precise intervals of fractions of a minute. More particularly, an L-shaped ribbon structure 48 is fastened to one end 49 of the conductive member or flexible arm 22. The L-shaped ribbon structure 48 has a first extremity 51 which extends from the flexible arm 22 towards the crank pins 36. The second extremity 52 forming the L-shaped ribbon structure 48 joins to the flexible arm 22. In cases where the L-shaped ribbon structure 48 is constructed from conductive material, a piece of insulating material 53 is sandwiched between the conductive flexible arm 22 and second extremity 52. A nylon rivet 54 is employed to fasten the L-shaped ribbon stlucture 48 and insulating material 53 to the flexible arm 22. Such a construction electrically isolates the L-shaped structure 48, hence, crank pins 36 from the conductive member or flexible arm 22.

The end portion 49 of the flexible arm 22 carrying the L-shaped ribbon structure 48 is canted from the main body 56 of the flexible arm 22 so that the crank pin engaging extremity 51 of the L-shaped ribbon structure 48 extends in the direction generally radially from the arbor 13 carrying the carrier 18. With the extremity 51 arranged in this fashion, the contact time between the extremity 51 and the crank pins 36 is minimized whereby successively circumferentially located crank pins 36 can be positioned to operate the switch contacts 19 and 21 at times separated by as little as thirty seconds. Insulating varnish 55 is provided at the end of the flexible arm 22 proximate the cam 42 to prevent accidental electrical connection between the conductive flexible arm 22 and the crank pins 36.

As explained hereinbefore, depending upon the location of the fulcrum about which the flexible arm 22 bends relative to the switch contacts 19 and 21, the cam 42 will either effect a switch closure or opening. In the illustrated embodiment, the fulcrum is located to effect a switch closure. The fulcrum is formed by anchoring the end 51 of the flexible arm 22 distal the cam 42 to the carrier 18 by the screw 24. The opposing switch contacts 19 and 21 are joined to the conductive members 22 and 23 to be located inbetween the screw 24 and cam 42 locations on the flexible arm defining the conductive member 22. The flexible arm 22 is mounted about the conductive member '23 to carry the switch contact 19 out of engagement with the opposite switch contact 21 unless the cam 42 engages a crank pin 36. One arrangement for effecting a switch opening would be to locate the fulcrum medially of the conductive member 22 with normally engaging switch contacts at the end 57 of the member 22 distal the cam 42. Instead of a flexible arm type conductive member 22, a rigid arm pivoted at the middle could be employed to effect a switch opening.

The ribbon construction of the crank pin engaging cam 42 enables the switch contacts 19 and 21 to be operated at intervals spaced only fractions of a minute apart. However, to realize precise timing, the crank pins 36 must be set so that they are engaged by the cams 42 precisely at the exact time desired. With particular reference to FIGURE 4, the precise timing is accomplished by providing means 58 for exactly setting the time indicating hand 14 at zero relative to the crank pin 36 which is engaged by the cam 42 when the time indicating hand is at zero on dial 16. Referring to FIGURE 1, the numbers associated with the arcuate slots 43 indicate the upper time limit of the two minute intervals during which the crank pins 36 can be set to engage the cam 42. Hence, the crank pin 36 associated with the arcuate slot 43 identified by the marking can be set to engage the cam 42 during the last two minute interval, i.e., from ninety-four to ninety-six minutes, of the ninety-six period, with the ninety-six minute point in the period corresponding also to the zero point in the period.

To exactly set the time indicating hand 14 to zero, the means 8 includes a switch 59 connected in series with the primary source of power, for example, the conventional AC line voltage, and the synchronous drive motor 61. The synchronous drive motor 61 is connected across the lines 62 and 63 delivering power from the AC line voltage source to cause the motor 61 to drive the arbor 13, hence, the time indicating hand 14 and carrier 18, and the desired rate. In setting the time indicating hand 14 to Zero, the switch 59 is opened (as shown in FIGURE 4) to disconnect the drive motor 61 from the AC line voltage power source. A lamp 65 is provided to indicate when the drive motor 61 is inactivated. The time indicating hand 14 carried by the arbor 13 to which the carrier 18 is secured is turned manually about the dial 16 by, for example, a knob 64 (see FIGURE 1) fixed to the end of the arbor 13. The switch contacts 19 and 21 are electrically connected in series with a current responsive indicating means or alarm 66 which together are electrically connected between the lines 62 and 63 in parallel with the serially connected switch 59 and motor 61. In this particular embodiment illustrated, the stationary brush 32 on the terminal board 34 is connected to the line 62 thereby connecting the switch contact 21 thereto. The stationary brush 33 connected to the switch contact 19 carried by the flexible arm 22 is connected to one side of the alarm coil 66, with the other side of the alarm coil 66 connected to the line 63. In this manner, the hell can be activated by closing the switch contacts 19 and 21 even 6 though the drive motor 61 is inactivated by opening the switch 59.

As the time indicating hand 14 is turned manually towards the zero point on the dial 16, the cam 42 is rotated with the carrier 18. The crank pin 36 located in the arcuate slot 43 identified by the 00 marking is positioned in the most inward point of the slot 43. Hence, when the time indicating hand 14 reaches the point on dial 16 corresponding to zero relative to the location of the crank pins 36 about the dial 16, the cam 42 will engage the inwardly positioned crank pin 36 thereby closing the switch contacts 19 and 21 to cause the alarm 66 to be sounded. At this instant the manual rotation of the time indicating hand 14 is terminated and the crank pin 36 engaging the cam 42 returned to the outer location of the slot 43. The time indicating hand 14 is exactly at the zero point of the ninety-six minute period and the timing mechanism thusly ready to provide switch contact operations to operate, for example, external mechanisms connected to the convenience outlet 67 connect in series with the switch contacts 19 and 21 at precise times and at intervals spaced as close as fractions of a minute. Accurately zero-setting of the time indicating hand 14 provides the precise timing capability because each of the arcuate slots 43 are spaced exactly at regular intervals corresponding, in the illustrated example, exactly to two minutes.

While the present invention has been described with respect to a single illustrated embodiment, numerous modifications and variations are possible within the scope of the present invention.

What is claimed is:

1. In a timing mechanism of the type including crank pins circumferentially located at regular intervals about a dial and mounted for selective movement into and out of position for engagement with a cam for operating switch contacts which cam is positioned to be surrounded by the circumferentially located crank pins and is rotatably mounted to an arbor carrying a time indicating hand driven by a power drive, the improvement comprising, a carrier member mounted to said arbor to rotate therewith, first and second conductive members mounted insulatingly apart on said carrier member, one of said conductive members mounted for movement toward the other, each of said conductive members carrying one switch contact located opposite the switch contact carried by the other conductive member, said cam including a ribbon structure mounted to said conductive member mounted for movement toward the other conductive member, said ribbon structure extending from the conductive member towards the circumferentially located crank pins to be normally out of engagement with the crank pins and to contact crank pins when moved into position for engagement with said cam, said ribbon structure eflecting relative movement between said conductive members to operate the switch contacts upon engaging the crank pins, means to inactivate the power drive operating the time indicating hand, indicating means, a source of power in circuit connection with said indicating means to operate the indicating means, means to electrically connect the switch contacts in series with the indicating means and the source of power so that the indicating means is activated by the source of power when the ribbon structure engages a crank pin, and manually operable means for turning the arbor joined to the carrier member.

2. The timing mechanism according to claim 1 wherein said power drive is an electrical drive motor, said inactivating means is a switch, said electrical drive motor and switch is electrically connected in series with said source of power, said serially connected switch contacts and indicating means electrically connected in parallel with the serially connected electrical drive motor and switch.

3. The timing mechanism according to claim 1 wherein said conductive member mounted for relative movement 7 towards the other conductive member is a flexible arm mounted above the conductive arm to maintain said switch contacts normally separated, and said ribbon structure mounted on said flexible arm to close said switch contacts when engaging crank pins.

4. The timing mechanism according to claim 3 wherein said flexible arm is secured to said carrier at one end thereof, said ribbon structure is mounted at the end of said flexible arm opposite the end secured to the carrier,

and the switch contact is mounted between the ends of the flexible arm.

5. The timing mechanism according to claim 4 wherein said ribbon structure is an L-shaped member having first and second extremities, said second extremity is mounted to the flexible arm, and said second extremity extends towards the crank pins.

6. The timing mechanism according to claim 5 further including an insulating member interposed between the second extremity and the flexible arm to electrically isolate the flexible arm from the L-shaped ribbon structure.

7. The timing mechanism according to claim 6 further including an insulating coating on the side of the flexible arm facing the crank pins over a portion of the end of the flexible arm proximate the L-shaped ribbon structure.

8. The timing mechanism according to claim 1 wherein said crank pins are positioned at locations about the dial corresponding to two minute intervals of the time interval corresponding to a single revolution about the dial of the time indicating hand carried by the arbor.

9. The timing mechanism according to claim 8 wherein said dial is graduated in minutes.

10. In a timing mechanism of the type including crank pins circumferentially located at regular intervals about a dial and mounted for selective movement into and out of position for engagement with a cam for operating switch contacts which cam is positioned to be surrounded by the circumferentially located crank pins and is rotatably mounted to an arbor carrying a time indicating hand driven by a power drive, the improvement comprising, a carrier member mounted to said arbor to rotate therewith, a stationary conductive member mounted on said carrier, a flexible conductive arm mounted on said carrier insulated and spaced above said stationary conductive member, one switch contact located medially on said flexible arm, the other switch contact mounted on the stationary conductive member opposite the switch contact on the flexible arm to be normally separated therefrom, an L-shaped ribbon structure having first and second extremities, said second extremity secured to said flexible arm at the end thereof opposite that which is secured to the carrier, said first extremity extending towards the circumferentially located crank pins to be normally out of engagement with the crank pins and to contact crank pins when moved into position for engagement with said cam, said L-shaped ribbon structure bending said flexible arm toward said stationary conductive member to close said switch contacts upon engaging the crank pins, and means to electrically connect the switch contacts to an electrical circuit.

References Cited UNITED STATES PATENTS 2,098,965 11/1937 James. 2,207,394 7/ 1940 Babcock 307-141 2,790,862 4/1957 Montgomery 307--141.8 2,797,270 6/ 1957 Yates 307-14l.8 2,806,910 9/1957 James. 3,348,008 10/1967 Miller 307-141 ROBERT K. SCHAEFER, Primary Examiner.

H. O. JONES, Assistant Examiner. 

